Gauge



Dea, 24, 1929 C, E, JOHANSSON 1,740,695

GAUGE Original Filed April l2, 1923 Patented Dec. 24, 1929 PATENT OFFICECARL EDVARD JOHANBSON, 0F DETROIT, MICHIGAN GAUGE Application lled April18, 1923, Berlaljlo. MMM,l and in Sweden April 27, 1922. RenewedSeptember 18, 1928.

placed in contact with the objects t0 be measured, and which gauges areprovided with two pointers one of which serves for the preliminary orrough measurement, for instance during the first stages of the working,and is actuated by the sliding measuring stud, and the other of whichserves for the accurate measurement and is actuated through a gearmechanism so that it gives a greater deviap tion than the first namedpointer for the same movement of the measuring stud. The object of theinvention is to provide a gauge of this kind which shall have smalldimensions and yet possess a large measuring range and whichsimultaneously renders possible very accurate measurements within acertain portion of said measuring range where articularly great accuracyis desired. Fort is purpose the invention consists broadly in that thegear mechanism is so constructed that the accurate measurement pointermoves only when the pointer actuated by the sliding measuring stud movesin the Vicinity on both sides of the zero point on a scale for saidpointer, but is released and will therefore be at rest during the othermovement of the 'rough measurement pointer. In this manner it ispossible to use a comparatively short scale and thus to obtain smalldimensions of the gauge, and in addition the important advantage is alsoattained that, for instance when measuring a piece of work in the courseof its manufacture, the accurate measurement pointer will begin to moveonly when the rough measurement pointer approaches the correct measureand thus indicates to the ma chinist that the piece of work approachesthe correct measure, so that greater caution must be observed during therest of the operation.

The present invention also contemplates a further improvement of theindicating device for the purpose of making possible a simpler and lessexpensive manu acture of the same and to render it possible to make thegauge of such shape that its range of usefulness will be increased. Forthis purpose the two pointers are ivoted on a common axis and areactuated a lever inserted between said pointers an the sliding measuringstud, the one short arm of said lever being actuated by the measuringstud, and diierent lengths of the other longer arm of said leveractuating the two pointers in such manner that one of said pointers`performs a greater movement than the other pointer for the samemovement of the measuring stud. By this insertion of a lever between themeasuring stud and the two pointers it is possible to make the narrowportion of the gauge nearest to the measuring stud of a sufficientlength for making it possible to measure also long holes of smalldiameter, and the serviceableness of the gauge is thus increased.

The accompanying drawings illustrate by way of example two embodimentsof the invention. Fig. 1 shows a gauge for measuring internal dimensionsconstructed according to the invention, in side elevation and in sectionthrough the head on the common axis of the two measuring studs, and Fig.2 shows a longitudinal section of the gauge. Fig. 3 shows a sideelevation, partly in section, of a second embodiment, of which Fig. 4shows a longitudinal section. Fig. 5 is a fragmentary View showing amodification of the embodiment illustrated in Fig. 3 adapted formeasuring external dimensions. Fig. 6 is an end elevation of the gaugeshown in Figs. l and 2.

The gauge illustrated in Figs. 1 and 2 consists of a head 1 which issecured to a hollow l shaft 2 the portion of which adjacent the head 1is formed as a box 3 covered by a transparent cover 53, said boxcontaining a gear mechanism and two pointers with corresponding scales.In the head 1 there are 'provided an adjustable measuringstud 4, asliding measuring stud 5 and two sliding, locating studs- 6. Theadjustable measuring stud 4 is screwthreaded into the head and may belocked in its position after adjustment for instance by means of a setscrew 7. The movable measuring stud 5 slides freely with its i nncrthick part in a bore in the head l, while its o uter portion which is ofa slightly smaller diameter, slides in the bushing 8 which 1sscrewthreaded into the head and which simultaneously serves to preventthe measuring stud from dropping out of the head. Against the innerplane end of the measuring stud the knife-shape extension 9 of a pivotedarm bears. Said arm carries a pointer 10 and is ivoted on the screw 11which is threaded into the bottom of the box 3, and the pointeris'actuated by a spring 12 which maintains the edge 9 bearing againstthe inner end surface of the measuring stud 5. The spring 12 tends toturn the pointer 10 to bear against a stop 13 projecting from the bottomof the box. pressure inwards on the measuring stud 5 will move thepointer 10 away from said stop until its movement is finally checked bya Stop screw 14 screw-threaded into the side Wall of the box 3.

On the side of the fulcrum 11 opposite the edge 9 the pointer arm isprovided with a second edge l5 directed in the oppositel direction, bymeans of which edge the pointer actuates a second pointer 16 of slightlyshorter length. Said pointer 16 is pivoted on a pin 17 in a bearing 18whichis secured by means of a screw 19 to the bottom of the box 3 andwhich may be adjusted in proper position by means of two set screws 20.A coil spring 21 maintains the pointer 16 in engagement with the edge l5and tends to turn the pointer against the stop 13. The edge 15 engages te pointer 16 in a plane through the point of the pointer and its axis ofrotation 17. When the measuring stud 5 is free and left to itself thespring 12 determines the position of said measuring stud as well as thepositions of the two pointers 10 and 16,

the spring 12 being stronger than the spring 21, so that the edge 15 onthe pointer 10 moves aside the pointer 16.

The two pointers 10 and 16 move over separate portions of a scale 22which is provided with two zero points, one for each pointer. The gearmechanism between the two pointers is so dimensioned, in the embodimentillustrated, that when the pointer 10 points to the zero point on thelower half provided for the same of the scale 22 in Fig. 1, the pointer16 also points to the zero point on the upper portion provided for thesame of the scale, and that for the same movement of the measuring stud5 the point of the pointer 16 moves through ten times the distancecovered bythe point of the pointer 10, so that if, for instance, themovement of the pointer 10 from one line to the next on the lower halfof the scale represents a movement of the measuring stud 5 of 0.1 mm.,the movement of the pointer 16 from one line to the next on the upperhalf of the scale represents, a movement of the measuring stud 5 of 0.01mm. The pointer Vin the bottom of the box In accordance scale, whereasduring the movement of the pointer 10 over the remaining portion of thelower half of the scale the pointer 16 is at rest bearing against thestop 13. By this arrangement of two pointers cooperating in the mannerabove described the essential advantage is attained that with acomparatively short scale and short pointers and consequently smalldimensions of the box 3 it is possible to take rough measures within alarge measuring range, for instance during the first stage of theworking, and also accurate measurements with very great accuracy withinthat portion of the measuring range of the gauge where the greatestaccuracy is required, that is to say in the immediate vicinity of thecorrect measure which is attained when both pointers point to theirrespective zero points.

ln certain cases it may be desirable to be 'able to lock the pointer `10in any position on tubular shaft 2 of the gauge. Said device con-` sistsof a piston 27 movable in the cylindrical cavity of the shaft 2 andactuated by a coil spring 26. To said piston 27 a rod 28 is securedeccentrically, said rod extending behind the bottom of the box 3 to a'lat'spring 29 secured at one end to said bottom. Said spring 29 isprovided at its other end with a portion 30 bent approximately at rightangles to the spring and projecting into an opening 3, in the vicinityof the screw 11. When the piston 27 is allowed to move to the left inFig. 2 under the actuation of its spring 26, the end of the rod 28actuates the spring 29 and forces the portion 30 of the same through theopening in the bottom of the box and against the pointer 10 which isthus forced against the head of the screw 1l. When the piston 27 ispulled back, to the right in Fig. 2, by the aid of a knurled head 25 ona reduced portion of said piston, the rod 28 releases the spring 29which in its turn releases the pointer 10. In this retracted positionthe piston 27 may be locked against the action of the spring 26 byslightly turning said piston 27 so that the neck of a button 31 securedto the piston and projecting through an angular slot 32 in the wall ofthe shaft 2, is moved into the portion of said slot 32'which isperpendicular to the longitudinal direction of the shaft 2. If it isdesired, while measuring, to fix the position of the pointer 10 on thescale 22, it is only required to turn the piston 27 so that the button31 moves out of the said portion of the slot 32, after.

which the spring 26 moves the piston 27 to the left in Fig. 2, so thatthe rod 28 forces the portion 30 of the spring 29 against the pointer 10with the result that said pointer 10 and thus also the pointer 16 arelocked in their respective positions.

W'hen the gauge described is to be used for measuring it is tirstintroduced into a snap gauge formed or built up of standard measuringblocks and shanks` or' into a standard ring of the desired exactdimension. The adjustable measuring stud 4 is now turned until bothpointers 10 and 16 point to their respective zero points, after whichthe measuring stud 4 is locked in its position thus determined. By meansof the gauge adjusted in this manner it is afterwards possible toobserve the making of a hole or a slot in a piece of work, while saidpiece is secured in the machine, from the time when about 2 mm. remainuntil the attaining of the desired measure, and when the machining hasbeen finished it is possible to ascertain whether the diameter of thehole or the width of the slot is exactly equal to the standard measureor otherwise is within the allowances over or under size.

In measuring a hole, suoli as indicated by the dot and dash circle inFig. 6, for example, both measuring studs 4 and 5 should be on the samediameter so that the correct dimension will be obtained. Such locatingof the gauge in the correct position is considerably facilitated by thetwo locating studs 6, which are secured to a sliding plate 4T located ina recess 48 in the head 1 and covered by a cover 49 secured to the headby screws 50. Said plate is pressed outwardly by two strong coil springs51, located in bores 52 in said plate and pressing against the bottomsof said bores and against the upper wall of said recess 48, thus tendingto move the studs 6 in a downward direction, as shown in Fig. 6, so

. that their outer ends will bear against the wall ot' the hole and thuscenter the instrument.

In the embodiment above described the box 3 is arranged in such mannerthat its center line is perpendicular to the common axis of the twomeasuring studs. Such arrangement, however, is not necessary, as it isof course also possible, if desired or suitable for any special purpose,to arrange the box more or less obliquely to said axis.

The gauge illustrated in Figs. 3 and 5 is also provided with anadjustable measuring stud 4 and a sliding measuring stud 5 which arelocated in alignment. the latter in the body 1 and the former in an arm33 projecting from said body, and also with two pointers 10 and 16 whichare movable over different portions of the scale 22, and the former ofwhich is used for rough measuring and the latter of which serves for thefinal accurate measuring. Both pointers are rotatable on a common pivot34 secured in the body 1, and each pointer is actuated by a flat spring35 and 36 respectively which tend to move the pointers against a stoppin 37. According to the invention there is inserted a level' 38 betweenthe sliding stud 54 and the two pointers, said lever\be1ng pivoted on ascrew 39 secured in the body 1, and the short arm of the lever beingactuated b the measuring stud 5 while the long arm o the lever actuatesthe two pointers.

In order to render possible adjustment of the ratio between themovements of the measuring stud and the pointers the lever is providedat both ends with slides 40 and 41 which are movable in longitudinalslots 23 and 24 respectively in the lever and may be secured in adjustedpositions by means of screws 42 and 43. The slide 40 at the end of theshort arm of the lever carries an edge 44 which bears against a planeshoulder on the measuring stud 5, so that when the measuring stud slidesthe lever 38 will be turned. The slide 41 at the end of the long arm ofthe lever carries in similar manner an edge 45 which bears against aplane surface on the accurate measurement pointer 16. The roughmeasurement pointer 10, on the other hand, bears with an edge 46directly against the lever 38. By adjusting the slide 40 it is thuspossible to adjust the ratio between the movements of the measuring stud5 and the rough measurement pointer 10, and by adjustment of the slide41 itis possible to adj ust the ratio between the movements of the twopointers.

As in the irst embodiment the pointers 10 and 16 move over differentportions of the scale 22 which is also in this embodiment provided withtwo zero points, one for each pointer. The gearing between the twopointers is arranged in such manner that when the pointer 10 points tothe zero point on the upper portion of the scale, the pointer 16 alsopoints to the zero point of the lower half of the scale. and the gearingmay be so adjusted in the manner above described that for the samemovement of the measuring stud 5 the point of the pointer 16 movesthrough ten times the distance covered by the point of the pointer 10.Also in this case the accurate measurement pointer 16 performs movementonly during the movement of the rough measurement pointer 10 in thevicinity on both sides of the .upper zero point on the scale, and willthen reproduce the simultaneous movement of the pointer. 10 in anenlarged scale, whereas during the movement of the pointer 10 over theremaining portion ot' the upper half of the scale, that is tol saybefore the accurate measuring is to begin, the pointer 16 is at rest andbears against the stop pin 37. This pin also prevents the pointer 10from moving more than one line below the upper zero point on the scale.During the rough lil) measuring, when only the pointer 10 moves, themeasuring pressure is determined by the tension of the spring 35, butduring the accurate measuring, when both pointers move, the

measuring pressure is determined by the difference between the tensionsof the two springs 35 and 36. The spring 35 must therefore be strongerthan the spring 36.

The gauge is primarily intended to be used for measuring internaldimensions, for instance the diameter of a hole. By the insertion of thelever 38 between the measuring stud 5 and the two pointers the advantageabove referred to is attained that the gauge may be used for measuringalso long or deep holes of small diameter. The gauge may easily bechanged, however. in such manner that it will also be serviceable forexternal measurements. Fig. 5 illustrates a modification of th'e gaugeshown in Fig. 3 adapted for external measurements. This embodiment ydiii'ers from the one illustrated in Fig. 3 only in that the arm 33awhich supports the. meas uring .stud 4, is located on the saine side ofthe body 1 as that on which the sliding measuring stud 5 projects. Thestud 4 is thus directed towards the stud 5, so that the object to -bemeasured, may be introduced between said studs. In other respects thisgauge is constructed similarly to that shown in Fig. 3, and similarreference numerals are used to denote similar parts. As regards theindications on the scale it is to be noted that in respect of internalmeasures the lines between the two zero points of the scale denote minusor undersize allowances, whereas in respect of external measures saidlines denote plus or over-size allowances.

I claim:

1. In a gauge the combination of a frame, two measuring studs in saidframe, one of said studs being adapted to slide in said frame, a roughmeasurement pointer actuated by said sliding stud, a scale for saidpointer having a zero point, an accurate measurement pointer, and meansadapted to transmit motion from said sliding stud to said accuratemeasurement pointer only when said rough measurement pointer moves inthe vicinity of the zero point on the scale, such movement of saidaccurate mea-surement pointer being at greater angular Velocity than themovement of said rough measurement pointer.

2. In a gauge the combination of a frame, twofmeasuring studs in saidframe, one of said studsl being-adapted to slide in said frame, a roughmeasurement pointer actuated by said sliding stud, a scale for saidpointer having a zero point, an accurate measurement pointer, a stop forsaid accurate measurement pointer, a spring tending to-turn saidaccurate lmeasurement pointer against said stop, and motion-multiplyingconnection between said sliding measuring stud. and said accuratemeasurement pointer `adapted to transmit motion from said sliding studto and to turn said accurate measuring pointer against the action ofsaid spring when said rough measurement pointer is in the vicinity ofthe zero point on said scale, such movement of said accurate measurementpointer being at greater angular .velocity than the movement of saidrough measurement pointer. A

3. In a gauge the combination of a frame, two measuring studs in saidframe, one of said studs being adapt-ed to slide in said frame, twomeasuring pointers, a scale :tor said pointers having a zero point, acommon pivot for said pointers, a lever one arm of which engages saidsliding stud and the other arm of which engages at different points ot'its length said two pointers in suchV manner as to cause said pointersto turn with ditferent angular velocities and to transmit motion to oneof said pointers only when the other of said pointers moves in thevicinity ot' the zero point on said scale.'

4. In a gauge the combination of a frame, two measuring studsin saidframe, one of said studs being adapted to slide in said frame, twomeasuring pointers, a scale for said pointers having a zero point, acommon pivot for said pointers, a lever, slides at both ends of saidlever adjustable in the longitudinal direction of the same, each slidehaving an edge, one of said edgesengaging said sliding stud, and theother of said edges and a surface on said lever engaging said twopointers in such manner as to cause said pointers to turn with differentangular velocities and to transmit motion to one of said pointers onlywhen the other of said pointers moves in the vicinity of the zero pointon said scale.

5. In a gauge the combination of a frame, two measuring studs in saidframe, one of said studs being adapted to slide in said frame, twomeasuring pointers, a scale for said pointers having a zero point, andmeans transmitting motion from said slidable measuring stud to saidpointers in such manner as to cause said pointers to turn with differentangular velocities and to operate one of said pointers only when theother of said pointers moves in the vicinity of the zero point'on saidscale,

6. In a gauge the combination of a frame, two measuring studs in saidframe, one of said studs being adapted to .slide in said frame, a roughmeasurement pointer, a scale for said pointer having a zero point, anaccurate measurement pointer, and a motioninultiplying connectionbetween said sliding measuring stud and said accurate measurementpointer adapted to transmit motion from said sliding stud to saidaccurate measurement pointer only when said rough measurement pointermoves in the vicinity of the zero point on the scale, such movement ofsaid accurate measurement pointer being at greater angular velocity thanthe movement of said measurement pointer.

7. In a gauge the combination of a frame, two measuring studs in saidframe, one of said studs being adapted to slide in said frame, twomeasuring pointers, a scale for .said pointers having a zero point, alever one arm of which engages said sliding stud and the other arm ofwhich engages at different points of its length said two pointers insuch manner-as to cause said' pointers to turn with different angularvelocities and to transmit motion to one of said pointers only when theother of said pointers moves in the vicinity of the zero point-on saidscale.

8. In a gauge the combination of a frame, two measuring studs in saidframe, one of said studs being adapted to slide in said frame, twomeasuring pointers, a scale for said pointers having a zero point, alever, one arm of which engages said sliding stud and the other arm ofwhich engages at different points of its length said two pointers insuch manner as to cause said pointers to turn with dii'erentangularvelocities and to transmit motion to one of said pointers only when theother of said pointers moves in the vicinity of the zero point on saidscale, the ends of said lever being adjustable to vary the effectivelength thereof.

9. In a gauge, the combination of a frame, two measurmg studs carried bvsaid frame, one of said studs being movable with reference to saidframe, a rough measurementpointer actuated by said movable stud. a scalefor said pointer having a zero point, an accurate measurement pointer,and means adapted to transmit motion from said movable stud to saidaccurate' measurement pointer only when said rough measurement pointerImoves in the vicinity of the zero point on the scale, such movement ofsaid accurate measurement pointer being at greater angular velocity thanthe movement of said rough measurement pointer.

10. A. gauge comprising a frame, two contact members carried by saidframe, one of which is movable, a scale, two pointers movable thereoverby said movable contact member, and means co-operating with said movablemember and with said two pointers whereby the latter jointly indicatethe desired reading.

11. A gauge comprising a frame, two contact membercarried by said frame,one of which is movable, a scale, two pointers movable thereover by saidmovable contact member, and means co-operating with said movable memberand with said two pointers whereby the latter jointly indicate thedesired reading, one of said pointers being movable through a greaterarc than the otheryfor giving a finer readin than said otherL 12. Adevice of t e class described comprising two pivotally mounted pointershaving a common axis of rotation, means arranged to act on said pointersat different distances from said axis, and a pair of relatively movablecontact members, one of which co-operates with said means, whereby thedistance between the contacting surfaces of said members is representedby two readings.

, 13. In a device of the class described, two 'pointers having a commonscale, means normally impelling said pointers in one direction to avoidbacklash, a pair of relatively movable contact members, connectionsbetween one of said members and one of said pointers, and connectionsbetween said first mentioned connections and the other of said pointerswhereby both pointers are actuated by said last mentioned Contact memberin opposition to said impelling means.

14:. In a device of the class described, a frame having a scale, twopointers each pivotally mounted on said frame, a movable contact member,connections between the same and one of said pointers to move the latterover said scale, a spring impelling said pointer in the oppositedirection, a stop for the second pointer, a spring normally impellingsaid pointer toward said stop, a projection on one of the movableelements oper-

